Joao Cancelo's move to Manchester City marks Pep Guardiola's latest upgrade to a position that has become pivotal to his all-conquering tactical approach.
Dani Alves and Eric Abidal starred in Guardiola's celebrated Barcelona side but he truly began to experiment and innovate with full-backs during his time at Bayern Munich.
In order to offset the counter-attacking threat of Bundesliga opponents, he began to deploy Philipp Lahm and David Alaba "tucked-in" alongside their defensive midfielder – a tactic that also aided the control of possession Guardiola so greatly craves. A source close to the Catalan tactician told Omnisport the internal positioning of full-backs is probably his biggest innovation.
Upon his arrival at City in 2016, the Bayern approach was briefly used. However, an aging group of fine club servants – Pablo Zabaleta, Gael Clichy, Bacary Sagna and Aleksandar Kolarov – were not up to the job, to varying degrees. As his team found their feet on the way to a third-placed Premier League finish in 2016-17, Fernandinho was even selected in both full-back positions.
In Guardiola's overhaul that close season, a transfer window that proved key to City's subsequent domestic dominance, the majority of a £221.5million outlay went on full-backs.
There have also been some less-likely solutions found and challenges remain at City in a defensive role the 48-year-old has revolutionised.
A weighty £50m acquisition from Tottenham, Walker has proved his worth as first choice throughout City's back-to-back Premier League title triumphs. The pace and athleticism that became his calling card and White Hart Lane were to the fore in an astonishing goal-line clearance during Sunday's Community Shield encounter against Liverpool, but the 29-year-old has proved himself to be a more adaptable performer than many considered.
Walker offers Guardiola in-game flexibility by being able to operate on the right of a back three – a role he also filled throughout England's run to the semi-finals of the 2018 World Cup. Having penned a five-year contract extension last month, it is possible his future could lie at centre-back.
Social media comedian and an instant cult-hero for City supporters, a succession of debilitating knee injuries mean the laughs have dried up for Mendy. When fit and firing, the £51.75m signing from Monaco offers a dynamic attacking option from deep and would help to shift the focus of City's attacks down the left if Leroy Sane joins Bayern Munich. At this stage, however, reaching and maintaining full fitness must be the France international's sole focus.
Heading in the other direction to Turin as a makeweight in the Cancelo deal, Danilo has rarely let City down when called upon. He enjoyed a brief period as first choice midway through last season when Walker's form waned at right-back but has largely been a victim of the England man becoming one of Guardiola's most trusted performers. Two seasons in Manchester yielded four Premier League goals, five major trophies and a Brazil recall for Russia 2018. Following a torrid time at Real Madrid, the 28-year-old's career is once again moving in the right direction as he begins a new chapter in Turin.
Mendy's injury woes forced Guardiola to be creative at left-back and Delph was his most unlikely success story of 2017-18. A career midfielder, he allowed Guardiola to revisit his Bayern template and started 21 league games in City's 100-point season. Form and fitness deserted Delph last time around and the emergence of another unlikely deputy paved the way for his departure to Everton.
An attacking midfielder by trade and a signing largely expected to be loaned out before being sold at a profit. However, Zinchenko never read that script and seemingly begins 2019-20 as Guardiola's first-choice left-back. Occasional shaky outings in 2017-18 did nothing to suggest such progress but his recovery from a goal-causing error to assist Sergio Aguero in a 3-1 win at Southampton last December proved a turning point.
He was superb as City won the first part of their domestic treble against Chelsea in the EFL Cup final, although Sunday's more torrid outing at Wembley when faced with Mohamed Salah showed the transition from stand-in to specialist can be tough - as Delph would attest.
Briefly assessed as an option amid Guardiola's full-back shortfall of 2016, Angelino was loaned to Girona, Mallorca and NAC Breda before joining PSV. An impressive 2018-19 in Eindhoven saw City trigger a buy-back clause for their former academy product, with Guardiola deciding specialist cover at left-back is a must as Mendy continues his latest rehabilitation. Some accident-prone moments in pre-season suggested the 22-year-old has work to do, though.
A technically assured player who attacks with the verve to be expected from a converted winger, Cancelo's skills appear to make him something close to the archetypal Guardiola full-back. His capacity for causing damage in the opposition half makes him a candidate to supply the threat Mendy has fleetingly provided on the opposite flank. Cancelo accounting for that natural width could in turn allow Gabriel Jesus to be fielded on the right of a front three, where he excelled during Brazil's triumphant Copa America campaign.
Talking of Brazilians, Cancelo has cited Alves as a key influence on his playing style. Having been frustrated when his former charge picked Paris Saint-Germain over City in 2017, Guardiola can content himself with having the latest model for his next innovations at full-back.